Dandy



April 4, 3-3-- I F. s. McDONNELL 1,903,311

DANDY Filed Sept. 15, 1,931

Patented Apr. 4, 1933 -UN1TED STATES FRANK s. MCDONNELL, or MILTON, ASSACHUSETTS 1 DANDY Application filed September 15, 1931. serial No. 562,843.

This invention. relates toa dandy mechanism for use with paper making machines. In manufacturing wove or otherwise watermarked paper, the wet web of pulp which has been formed on a Fourdrinier wire is run beneath a dandy roll, that is, a light roll which may he covered with wire screen for a wove finish or which maybe provided with a watermark design adapted to press upon the pulp web. These dandy rolls are subject to certain difficulties in that they are liable to pick up loose fibers and filling material from the pulp sheet so that the pores of the screen become more or less clogged. This disturbs the marking action of the roll and may cause the web to pull loose from the Fourdrinier wire. WVater which is expressed from the sheet by the pressure of the dandy roll thereon tends to collect within the roll up toa certain point, then to seep out again, disturbing the uniformity of the marking or finish of the sheet.

The present invention relates to improved mechanism by which the ordinary dandy v roll may be replaced by equivalent mechanism capable of overcoming the objectionable features of the usual dandy roll. The invention thus includes mechanism for removing the water expressed from the sheet by the pressure of the dandy, and suitable means for cleansing the wire screen which comes in contact with the surface of the pulp web.

invention reference may be had to the de scription thereof which follows and to the drawing, of which,

Figure 1 is a side elevation of an embodiment ofthe invention.

Figure 2 is a fragmentary section on the line 22 of Figure 1.

Figure 3 is a section on the line 3-3 of Figure 1. V

Figure 4 is a fragmentary elevation of a modified portion of mechanism shown in Figure 1.

Figure 5 is a side elevation of a cleaning brush for the wire screen used with the dandy.

For a more complete understanding of the Figure 6 is an elevation of a similar brush, with the ordinary dandy I'O1l..'

As indicated in Figure 1, I may substitute for the ordinary dandy roll an endless band of'wire screen 10 which may be passed about two or more suitable rolls, three such rolls 11,12 and 13 being shown. These rolls may be supported as by a suitable framework 14, the lower rolls a 11 and 12 being supported in adjustable bearings which, as shown, are capable'of both vertical and horizontal adjustment. lVithin the belt 10 is mounted a suitable trough 15 to receive wash water from a spray directed against the belt through suitable nozzles 16. Likewise with in the belt 10 is mounted a suction device 17, the suction nozzle 18 of which is in close proximity to the lower horizontal stretch 20of the wire 10, this stretch being adapted to press on the upper surface of a pulp web 21 which is carried by a travelling Fourdrinier wire 22 in the direction indicated by the arrow. The wire 22 with the pulp web thereon may pass over a pair of suction boxes 23 and 24 to assist in the removal of excess water from the web. The pressure of the lower stretch '20 of the wire 10 on the web tendsto cause some of the free water in the web to be forced upwardly through the wire 10. The suction nozzle 18 effectively removes this loose water on the upper surface of the stretch 20 of the wire 10. The suction box 24 may conveniently be placed beneath the roll 12 so that any additional free water expressed from the web 21 at this point may be drawn downwardly by the box 24.

Instead of the suction nozzle 18 I may provide a wiper or doctor 30, as indicated in Figure 4. This may be in the form of a strip of rubber extending diagonally across the lower stretch 20 of the dandy roll to collect and lead off to one side the loose water which comes up through the wire 10.

I may also provide a suitable brush 31 to clean the wire 10 instead of or in addition to the spray nozzle 16. This brush may be mounted to revolve freely and to be driven by its contact with the wire 10, or Imay provide means (not shown) for rotating the brush either in the same direction or in an opposite direction to the motion of the wire It is obvious that Various modifications and changes may be made in the structure herein described without departing from the spirit and scope of the invention as defined by the following claim.

I claim:

In a paper making machine, a pair of spaced lower rolls supported tangent to a pulp web produced on said machine, an upper roll above and laterally offset from said lower rolls, an endless foraminous belt passing around the three rolls, means for vertically adjusting each of said lower rolls, means for adjusting the upper roll to regulate the tension on said belt, suction means adjacent to the stretch of belt between said lower rolls, means for washing a stretch of belt between the upper roll and one of the lower rolls, and means for collecting and leading off the washing fluid.

In testimony whereof I have affixed my signature.

FRANK S. MODONNELL. 

